Office 365 Groups is not an app like Teams or Power BI, but a cloud feature for communication, coordinating group efforts and sharing information.
Groups allows users to create and manage ad hoc “groups” for collaboration, centralising membership for multiple Office 365 products in one place. This way you can apply policies at the project or team level instead of individually in Planner, Yammer, OneNote and SharePoint. Groups is the new and improved experience for what we used to use distribution lists or shared mailboxes to do.
Think of Groups as a keyring that holds all the collaboration keys together. It provides common access to applications and content to people working on a project, not necessarily in the same organisation. A Group is also an Active Directory object. Users can be provisioned and deprovisioned from Groups, like a single-sign-on system, with the addition of automated access to content.
Groups is included with any Office 365 subscription that has Exchange Online, plus SharePoint Online will support Groups. That includes the Business Essentials and Business Premium plans, and the Enterprise E1, E3 and E5 plans.
Collaboration: leverage the O365 tools you already use to collaborate when writing documents, working on project plans, scheduling meetings or sending email.
Access management: effectively allocating resources and permissions to multiple users.
Communication: both internal and external, using six different tools: OneDrive for Business, SharePoint, Yammer, Teams, Outlook and Skype for Business.
Channel confusion: with so many options for communication, the trick is working out which one(s) to use when.
Asset profusion: create a group in Outlook and you will get the following: